Manufacture of woven ladder webbing



12,,1958 R; FRENCH MANUFACTURE OF WOVEN LADDER WEBBING 2 Sheets-Sheet 1 Filed Jim 1, 1955' Aug. 12, 1958 FRENCH MANUFACTURE OF WOVEN LADDER WEBBING 2 Sheets-Sheet 2 Filed June 1. 1955 rite MANUFACTURE OF WOVEN LADDER WEBBING Roger French, Hale, England, assignor to Thomas French 8; Sons Limited, a British company This invention relates to the manufacture of woven ladder webbing, that is to say in general definition, to Webbing consisting of at least two main webs between adjacent pairs of which are located cross straps having their ends secured to the main webs by binding-in during weaving of the main webs. The invention relates particularly to woven ladder webbing of the kind hereinafter termed the kind referred to, in which, considered in the flat as it is woven, consecutive cross straps overlap in tegulated manner, that is to say each cross strap overlies an end of the next preceding strap and is overlaid in turn at its other end by the next succeeding straps; as distinct from earlier forms of ladder webbing in which the cross straps are arranged in two rows, with the cross straps in each row in staggered relation to those in the other row so that any cross strap in one row overlaps at each end, with the ends of two cross straps in the other row, but so that no cross strap actually overlies or is overlaid by another.

One of the problems of ladder webbing of the kind referred to is that of weaving the cross straps. Such weaving is desirable either for strengthening the same, as compared with unwoven warp threads, and/or to avoid the untidy appearance so easily presented by any such unwoven warp threads. Using a 4-tier or 4-bank loom to Weave the ladder webbing of the kind referred to, having two rows of cross straps, the straps in one row lying sideby-side with those in the other row, and overlapping with adjacent cross straps in their own row when the web is flat, the two intermediate shuttles are used one for each row to weave for their full length alternate cross straps thereof, leaving the Warp threads of intermediate cross straps unwoven so that each woven cross strap is side-byside with unwoven warp threads in the other row. It would obviously be possible, through less useful, to have the side-by-side pairs of cross straps woven and un woven alternately.

The present invention is an appreciation that for ladder webbing of normal proportions it is possible, where there are pairs of side-by-side cross straps, to weave so much of each that they are almost fully woven.

According to the present invention ladder webbing of the kind referred to is characterised in that all the cross straps are at least part woven and in that any unwoven part of any one cross strap is wholly overlaid by, or overlies, a woven portion of an adjacent cross strap in the same row, the warp threads at the ends of the bound-in portions of each cross strap (before cutting) passing through a woven portion of adjacent cross strapsin the same row, whereby a substantial part at least of all the cross straps may be woven without necessitating the use of an additional shuttle therefor.

As it is desirable that all unwoven portions of the cross straps shalt be as short as possible, in the preferred form of the invention the unwoven portions are equally distributed amongst both ends of all the cross straps in any one row, and the weft used for weaving such cross straps is not used during the binding-in, but crosses over immediately to the over-lying cross straps. Of course the shut- States Patent tles could be used so that the unwoven portions at one end of each cross strap are longer than that at the other end. Obviously also, should it be desired to have some of the cross straps wholly woven, again at the expense of increasing the length of the unwoven portions in the other cross straps, alternate cross straps may be fully woven necessarily leaving unwoven portions at each end of the intermediate cross straps. In no instance is the weft of an intermediate shuttle used to help the bindingin as this increases the length of the unwoven portions.

In the accompanying drawings:

Fig. l is a diagrammatic side elevation of Fig. 2;

Fig. 2 is a perspective view showing a preferred embodiment of the invention;

Fig. 3 shows a modification of the ladder webbing shown in Fig. 2;

Fig. 3A shows a further modification of the example shown in Fig. 3; I

Figs. 4 and 5 show further modifications of the ladder webbing.

As shown in Figs. 1 and 2. the ladder web consists of two mains webs 10 and 11 between which are two rows of cross straps 12 and 13 respectively. All cross straps are fully woven at their central sections but each has an unwoven portion 12a and 13a respectively at each end. In the process of weaving, the warps are carried across in known manner, as shown at 1312 for the cross straps 13, after a binding in to secure one end of a cross strap to one main web and for binding in to the other main web the end of the next consecutive cross strap in the row before starting the said next consecutive cross strap. These cross overs for the warps are usually termed the short cross overs and are of the order of A; inch in length, though shown much longer in Fig. l for diagrammatic reasons and are severed after weaving to free the fabric and form the ladder-like appearance of such webbing. The unwoven portions 12a and 13a are shown about Ms inch long as twice that is the overlie of the ends of the consecutive cross straps in the same row to provide overlap for the slats which are supported on such cross straps in the construction of a Venetian blind. Thus, each cross strap overlies oneend of the consecutive cross strap and in turn is overlaid at its other end by the preceding cross strap in the same row. The ladder web has side-by-side cross straps 12 and 13 so that each of the slats may be supported for example on 12 and lie underneath a cross strap 13 which latter prevents undue movement or flutter of the laths in a breeze or air current. In the operation of weaving a carry over of weft can be seen in Fig. l where the weft of an intermediate shuttle is carried across to start weaving the next cross strap in the row before the whole length of the preceding cross strap has been woven. These weft cross-overs 130 are close to the warp cross overs 13b and are therefore easily cut by the operator or machine when cutting the warp cross-overs in normal manner.

In a further modification alternate straps 14 in each row are fully woven and are each side-by-side with a part woven cross strap 15, as shown in Fig. 3, both ends of 16 of such cross straps being necessarily left unwoven.

In Fig. 3A, which is a modification ofFig. 3, the cross straps are woven so that alternate side-by-side pairs 14a are fully woven and the intermediate side-by-side pairs 15a are part woven with both ends unwoven at 1611. The construction of Fig. 3 compared with this has the obvious advantage that there is a fully woven cross strap to support each of the slats while the partly woven cross strap has only to perform a holding action to prevent flutter.

As shown in Figs. 4 and 5, there is only a single row of cross straps and by this invention the weaving may be effected in a S-bank or 3-tier loorn to provide the same arrangement of weaving of the cross straps as shown in any one row of ladder webs shown in Figs. 2 or 3.

Thus, in Fig. 4, the ladder web consists of main webs 17 and 18 and one row of cross straps 19, all of which have unwoven portions 1917 at each end.

In Fig. 5, the cross straps are alternately fully woven as at 20 and part woven as at 21 with both their ends unwoven at 21a.

By this invention, for the first time it is shown to be possible to make ladder web on a 4-bank or 4-tier loom with two rows of side-by-side and over-lying cross straps yet with only small portions of some, or even smaller portions of all, the cross straps unwoven, a possibility hitherto never appreciated; whilst with only a 3-tier or 3- bank loom a very useful ladder web can be made which, though having only one row of over-lying cross straps has otherwise all the other advantages of the ladder webbing aforesaid made with a 4-tier or 4-bank loom.

Obviously, the length of the unwoven portions of the cross straps is a function of the length of overlie of consecutive cross straps and of the distribution of such necessarily unwoven length either to spread it between all cross straps or in alternate cross straps.

The invention is not limited to the examples above described as there are conceivably other forms of ladder webbing which can be woven without departing from the invention as herein defined and as a result of which continuous use can be made of the intermediate shuttle with advantages which will be obvious both in the product and/ or in the simplicity of producing the same, thus making it possible to produce a better or more fully woven ladder webbing than would otherwise have been possible with the facilities available.

I claim:

1. Uncut woven ladder webbing of the kind comprising at least two woven main webs between adjacent pairs of which is located at least one row of longitudinally at least partially in-line cross straps having their ends secured to the said main webs by binding in during the weaving thereof, characterised in that all the cross straps are at least part woven with each pick of weft thread extending completely throughout the width thereof and in that any partially unwoven cross strap is partially unwoven at each end and each unwoven part is wholly overlaid longitudinally by, or overlies, a woven portion of an adjacent cross strap in the same row, warp threads at the ends of the bound in portions of each cross strap passing through a woven portion of adjacent cross straps in the same row, whereby a substantial part at least of all the cross straps may be woven without necessitating the use of an additional shuttle therefor.

2. Uncut woven ladder webbing according to claim 1 further characterised in that each cross strap is partially unwoven and the unwoven portions of each cross strap representing the overlie at one end with an adjacent strap in the same row are equally distributed at the two ends of the strap so that the woven portion is disposed centrally of its length.

3. Uncut woven ladder webbing according to claim 1 further characterised in that alterntae cross straps in each row are wholly woven and in that the intermediate cross straps have unwoven portions at each end representing the overlie of those ends with the adjacent fully woven cross straps.

4. Uncut woven ladder webbing according to claim 2 in which all of the cross straps are identical.

5. Uncut woven ladder webbing according to claim 3 wherein said unwoven portions at each end of said intermediate cross straps are of equal length.

6. Uncut woven ladder webbing according to claim 3 wherein said alternate wholly woven cross straps lie in side-by-side relationship with alternate partly woven cross straps in an adjacent row of cross straps.

7. Uncut woven ladder webbing according to claim'3 in which said alternate wholly woven cross straps lie in side-by-side relationship with wholly woven cross straps in an adjacent row of cross straps.

8. Uncut woven ladder webbing of the kind comprising at least two woven main webs between adjacent pairs of which is located a longitudinally disposed row of cross straps having their ends secured to the said main webs by binding in during the weaving thereof, characterised in that alternate cross straps are wholly woven and in that the intermediate cross straps have unwoven portions at each end, any unwoven part of any one cross strap being wholly over-laid longitudinally by, or overlying, a woven portion of an adjacent cross strap, warp threads at the ends of the bound in portions of each cross strap passing through a woven portion of adjacent cross straps in said row, whereby a substantial part at least of all the cross straps may be woven without necessitating the use of an additional shuttle therefor, and each pick of Weft thread with which any cross strap is woven extending the full width of said cross strap.

9. Uncut woven ladder webbing according to claim 8 in which the unwoven portions of each cross strap representing the over-lie at one end with an adjacent strap in said row are equally distributed at the two ends of the strap so that the woven portion is disposed centrally of its length. 7 10. Uncut woven ladder webbing of the kind comprising at least two woven main webs between adjacent pairs of which is located a longitudinally disposed row of cross straps having their ends secured to the said main webs by binding in during the weaving thereof, characterised in that all of said cross straps have unwoven portions at each end, warp threads at the ends of the bound in portions of each cross strap passing through a woven portion of adjacent cross straps in said row, whereby a substantial part at least of all the cross straps may be woven without necessitating the use of an additional shuttle therefor, and each pick of weft thread with which any cross strap is woven extending the full width of said cross strap.

11. Uncut woven ladder webbing according to claim 10 wherein the unwoven portions of each cross strap representing the over-lie at one end with an adjacent strap in said row are equally distributed at the two ends of the strap so that the woven portion is disposed centrally of its length.

12. Uncut woven ladder webbing according to claim 10 in which all of the cross straps are identical.

References Cited in' the file of this patent UNITED STATES PATENTS Re. 22,925 Rasero Oct. 7, 1947 FOREIGN PATENTS 512,835 Great Britain Sept. 27, 1939 899,780 Germany Dec. 17, 1953 

